Outer blade for reciprocal type electric shaver

ABSTRACT

A perforated outer blade for reciprocating type electric shaver having an improved new pattern of hair inlet holes is provided. In a flat perforated thin metal plate of rectangular outline, a number of rows of generally slit-shaped hair inlet holes is formed between adjacent ones of a plurality of wavy ribs which are out of phase and generally longitudinally extending along axes spaced generally parallel to one another, with the lengthwise dimension of the holes varying depending on varying spacing between the wavy ribs. The holes in the same row are in two groups in which the lengthwise axes of the holes are slightly angled with respect to the rib axes at respectively different orientations.

United States Patent 1191 Sakai et al.

[ NOV. 4, 1975 OUTER BLADE FOR RECIPROCAL TYPE ELECTRIC SHAVER [73] Assignee: Matsushita Electric Works, Ltd.,

Osaka, Japan 22 Filed: Sept. 20, 1974 21 Appl. No.: 507,709

[30] Foreign Application Priority Data Oct. 8, 1973 Japan 48-113005 [52] US. Cl. 30/154651; D95/3 B [51] Int. Cl. B26B 19/04 [58] Field of Search 30/346-351; 1395/3 A, 3 B, 3 R

[56] References Cited UNITED STATES PATENTS 3,696,508 10/1972 Messinger 30/346.51 X 3,815,232 6/1974 Liska 30/346.51

FOREIGN PATENTS OR APPLICATIONS 961,649 5/1950 France 30/346.5l

1,113,006 3/1956 France 30/346.51

Primary ExaminerAl Lawrence Smith Assistant Examiner-Gary L. Smith Attorney, Agent, or FirmWolfe, Hubbard, Leydig, Voit & Osann, Ltd.

[57] ABSTRACT A perforated outer blade for reciprocating type electric shaver having an improved new pattern of hair inlet holes is provided. In a flat perforated thin metal plate of rectangular outline, a number of rows of generally slit-shaped hair inlet holes is formed between adjacent ones of a plurality of wavy ribs which are out of phase and generally longitudinally extending along axes spaced generally parallel to one another, with the lengthwise dimension of the holes varying depending on varying spacing between the wavy ribs. The holes in the same row are in two groups in which the lengthwise axes of the holes are slightly angled with respect to the rib axes at respectively different orientations.

3 Claims, 23 Drawing Figures U.S. Patent Nov. 4, 1975 Sheetlofll 3,916,522

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US. Patent Nov. 4, 1975 Sheet6of11 3,916,522

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US. Patent Nov. 4, 1975 Sheetllofll 3,916,522

Fig. 22

OUTER BLADE FOR RECIPROCAL TYPE ELECTRIC SHAVER This invention relates to improvements in perforated outer blades for reciprocating type electric shavers.

There are known conventional perforated outer blades for reciprocating type electric shavers wherein hair inlet holes are of the type of many round holes 21 arranged as illustrated in FIG. 1, of diamond-shaped holes 23 arranged around hexagonal holes 22 as illustrated in FIG. 2 or of the like holes.

However, in such conventional blades, there have been such defects that, in the case of only the round holes illustrated in FIG. 1, it will be difficult to introduce long hairs and that, in the case of the type shown in FIG. 2, the direction of the slit (or hair inlet hole) will not be fixed, the hair holding angle (between the inner blade and the inside edge of the slit) at the time of cutting a hair introduced into the slit will not be constant and, therefore, the cutting efficiency will fluctuate with the direction of the slit and troubles will be caused.

In view of the above, the present invention has been suggested to remove such defects of the conventional outer blades, by providing in a metal lamina a plurality of ribs sequentially varying in the spacings between them as spaced at proper intervals and also a plurality of slit-shaped hair inlet holes different in the length dimensions with a continuous variation between the adja' cent ones of the ribs.

An object of the present invention is, therefore, to provide an outer blade for electric shavers wherein hairs of different lengths can be efficiently introduced into the hair inlet holes.

Another object of the present invention is to provide an outer blade for electric shavers which is ofa uniform high cutting efficiency on the entire surface.

Another object of the present invention is to provide an outer blade for electric shavers which has a high opening density.

A further object of the present invention is to provide an outer blade for electric shavers which is high in the strength in the central part of the blade.

Now the present invention shall be explained with reference to preferred embodiments in conjunction with accompanying drawings, in which:

FIGS. 1 and 2 are plan views of conventional perforated outer blades;

FIG. 3 is a plan view of a perforated outer blade according to the present invention;

FIG. 4 is a perspective view of a reciprocating type electric shaver with a part removed, using the perforated outer blade illustrated in FIG. 3;

FIGS. 5 to 7 are plan views showing different embodiments of the perforated outer blade according to the present invention;

FIGS. 8 to 17 are explanatory views showing modified embodiments of the wavy ribs of the perforated outer blade according to the present invention;

FIGS. 18 through 22 are plan views showing further different embodiments of the perforated outer blade of the present invention; and

FIG. 23 is an explanatory view for the term hair holding angle used in describing the present invention.

Referring to FIG. 3, A is a perforated outer blade formed so as to be provided with a plurality of wavy ribs a substantially in parallel relation to one another and continuously varying in the spacing between them and spaced at proper intervals on such metal lamina l as of stainless steel and with a plurality of hair introducing holes or slits b made between adjacent ones of the wavy ribs a at proper intervals so that the slits adjacent to each other in the spaced direction 1 between the respective wavy ribs a may not be contiguous to each other, the surface area of each hole being made substantially constant. Through fitting holes 2 made on the end edges of said lamina, as shown in FIG. 4, said outer blade is set arcuately on the upper surface of a reciprocating inner blade 4 arranged in the head part of a body 3 containing a driving source so as to be in sliding contact with said inner blade so that a reciprocating type electric shaver C will be formed.

The above described hair inlet holes 11 may be formed by either such mechanical process as punching or such chemical process as corrosion.

FIGS. 5 to 7 show different embodiments of the perforated outer blade according to the present invention. FIG. 5 is of an embodiment wherein both ends of the hair inlet hole b of the embodiment illustrated in FIG. 3 are formed to be arcuate. FIG. 6 is of an embodiment wherein the hair inlet holes b are formed to be inclined so as to provide a hair holding angle a defined by the inclination and edge line of the reciprocating inner blade d, as shown in FIG. 23. FIG. 7 shows an embodiment wherein the wavy ribs a themselves are inclined relative to the end edges of the outer blade so as to provide the hair holding angle with respect to the reciprocating inner blade.

FIGs. 8 to 13 show modified embodiments of the wavy ribs. FIG. 8 is of an embodiment wherein the wavy ribs are of sine waves and the phases of the adjacent ones of wavy ribs a and a differ from each other by about FIG. 9 is of an embodiment wherein the phases of the wavy ribs of sine waves are deviated successively in turn by about 300 in the same manner as in FIG. 8. FIG. 10 is of an ernbodiment wherein the adjacent ones of wavy ribs a and a different in amplitude, phase and angular velocity of the sine waves, are arranged alternately. FIG. 11 shows an embodiment wherein the wavy ribs are of continuously bent straight lines. FIG. 12 is of an embodiment wherein the wavy ribs are made by varying the angular velocities of the sine waves in the X-axis direction. FIG. 13 is of an embodiment wherein the wavy ribs are made by varying the amplitudes of the sine waves in the X-axis direction. FIG. 14 shows an embodiment wherein a plurality of wavy ribs are so formed that the average spacing P between the adjacent ribs becomes gradually larger toward the end edge from the center and many hair inlet holes are formed between the adjacent wavy ribs a. FIG. 15 is of an embodiment wherein the phases of the adjacent wavy ribs are deviated successively in turn from each other so that the spacing between the ribs will be larger toward the end edge from the center. FIGS. 16 and 17 show embodiments wherein the wavy ribs are of sine waves, wherein FIG. 16 shows an embodiment in which the amplitude of the wave forms is made larger toward the end edge so that the spacing between the ribs will be larger and FIG. 17 shows an em bodiment in which the phases of the adjacent wavy ribs differ successively in turn from each other so that the spacing between the ribs is larger toward the outside.

In the further different embodiments shown in FIGS. 18 through 22, the present invention provides the outer blade of the type referred to but having more improved features. According to the foregoing embodiments already described, the hair inlet holes b are all oriented in the same direction generally along the direction I of spacing between the respective adjacent ones of the wavy ribs, that is, in said spacing direction or in a direction slightly angled with respect to the spacing direction or with respect to axes of the respective wavy ribs. In practice, on the other hand, beard hairs are not always oriented in a single direction and any beard hairs grown in a different direction from the orientation of the hair inlet holes are hard to catch or introduce into the holes. The further embodiments of FIGS. 18 through 22 are effective in improving this respect.

In the further embodiments, the wavy ribs a and hair inlet holes b are provided in the metal lamina 1 substantially in the same manners as in the foregoing embodiments of FIGS. 6 through 17. However, the hair inlet holes b in the embodiments of FIGS. 18 through 22 are arranged so that the hair holding angle a will be different at certain different regions of inside field enclosed by frame region of the outer blade A.

Referring in detail to FIGS. 18 through 22, FIG. 18 shows an embodiment of the outer blade A wherein a plurality of the hair inlet holes a distributed between each space between adjacent pairs of the wavy ribs a so as to form a row of the holes therebetween are so oriented as to form a hair holding angle a of 20 with respect to the cutting edge line of the inner blade. In particular, the orientation of the hair inlet holes in each row is made alternately in a different direction at every row of the hair inlet holes in this embodiment.

FIG. 19 shows an embodiment of the outer blade wherein, while the respective hair inlet holes b inthe respective rows are all arranged to have the hair holding angle a of 20, their orientation is made to vary in each one half region of each row in the outer blade A so that, in the present instance, the holes b of a group in left half region of the blade are oriented in a direction different from that of a group in right half region.

FIG. 20 is of an embodiment in which a row of the hair inlet holes b arranged to have the hair holding angle or 20 and a row of the hair inlet holes b arranged to have a hair holding angle a are alternately arranged.

In an embodiment shown in FIG. 21, the hair inlet holes b of the respective rows in the left half region group are arranged to have the hair holding angle a whereas the holes b of the respective rows in the right half region group are arranged to have the angle a 5.

In a further embodiment of the outer blade according to the present invention as shown in FIG. 22, the orientation of the hair inlet holes b is made different at a sequence of, in the present instance, every two rows, while the hair holding angle a itself is kept constant, that is, the angle a 20 in this embodiment over the whole field region of the outer blade A.

With the above described arrangements of the hair inlet holes b, the outer blade of the present invention enables it possible, in the case of the respective embodiments of FIGS. l8, l9 and 22, to render the hair introducing effect not to vary at each of left and right sides of users face as the hair inlet holes are all arranged to have a constant hair holding angle and to be oriented in two different directions and, in the case of the embodiments of FIGS. 20 and 21, to perform both a cursory shaving by means of the rows or group of the 4 hair inlet holes b having a larger hair holding angle and a finishing shaving by means of the other rows or group of the holes b of a smaller hair holding angle.

According to the present invention, as has been described earlier in the foregoing, it is made possible to have hairs of different lengths introduced into the hair inlet holes by so forming the slit-shaped hair inlet holes that the length and width of each hole will be substantially inversely proportional to each other.

By forming the slit-shaped hair inlet holes so that, further, the hair holding angle defined by the side edge of the slit and the side edge of the inner blade will be constant at any positions over entire field region of the outer blade in certain aspects of the invention, it is enabled to render the sharpness of the shaver to be even at all positions of the outer blade.

The hair cutting effeiciency can be further improved by making the opened part area of the hair inlet holes to be at least 40% of the entire surface area of the outer blade.

As referred to in the above, the present invention has many excellent effects including the following that there can be obtained an outer blade in which a number of hair inlet holes are formed between the respective wavy ribs so that hair inlet holes of different lengths ranging from round holes to slits can be formed to be present as mixed on the entire blade surface, short and long hairs can be efficiently introduced into the holes, the cutting speed is high and the cutting efficiency is also high, that there can be made an outer blade in which, by inclining the direction of the hair inlet holes to be in a fixed direction with respect to the reciprocating inner blade, the holding angle for the hair can be made constant at an optimum value and the cutting efficiency can be made uniform on the entire surface, that there can be simply obtained an outer blade favorable in the touch on the blade surface by freely selecting the optimum width of the slit which not hurting the skin depending on the length of the slit, and further that there can be obtained a perforated outer blade of a pattern high in the opening rate and artistic in the appearance.

Further, according to the present invention in some aspects described, there can be obtained an outer blade in which the rate of round holes and short slits is automatically high in the central part of the blade and the rate of long slits is high on the outside, and the mechanical strength can be increased in the central area which is most likely to be broken in practice of the outer blade.

Further according to the present invention, the area, i.e. the width x length, of each hole is substantially constant in all hair inlet holes over the entire blade, the amount of the skin projected out of each hole will be uniform and, as a result, beard hairs will be able to be cut uniformly and smoothly without hurting the skin.

According to the present invention in certain aspects, specifically in those of FIGS. 18 through 22, beard hair introducing or catching abilitycan be remarkably improved, as the hair inlet holes in alternate one or more rows or in the respective left and right half groups of the parallel rows are oriented in separate directions so that hairs grown in such separate directions can be more effectively introduced into each of such separately oriented rows or groups of the hair inlet holes as compared with the case where the whole hair inlet holes are oriented in a single direction.

What is claimed is:

1. In an outer blade for an electric shaver in the form of a flat perforated thin metal plate of rectangular outline capable of being bent into U shape for cooperating with a cyclically moving interior blade of conforming profile for shearing beard hairs, the combination comprising a plurality of ribs extending generally longitudinally along axes which are spaced generally parallel to one another, said ribs being of generally sinusoidal shape with adjacent ribs being out of phase with one another causing the spacing between them to continuously vary, and a plurality of rows of generally slitshaped and closely spaced hair inlet holes respectively defined between the adjacent ribs, said holes extending generally from rib to rib so that the length of the respective holes as measured generally from rib to rib varies in accordance with the varying spacing between the ribs, said plurality of hair inlet holes comprising (a) a first group of holes in which the lengthwise axes of the generally slit-shaped holes are oriented in a first direc- 6 tion slightly angled with respect to a perpendicular to the rib axes and (b) a second group adjacent thereto in which the lengthwise axes of the holes are oriented in a second direction angled differently from said first direction, said first and second groups of the hair inlet holes being located in each of the rows of the holes.

2. The combination as claimed in claim 1 in which said first and second directions of the hole orientation in the respective first and second groups are angled by the same degree with respect to the rib axes so that hair holding angle for shearing will be constant over both groups of the holes.

3. The combination as claimed in claim 1 in which said first and second directions of the hole orientation in the respective first and second groups are angled by different degrees with respect to the rib axes so that hair holding angle for shearing will be different in each of the groups. 

1. In an outer blade for an electric shaver in the form of a flat perforated thin metal plate of rectangular outline capable of being bent into U shape for cooperating with a cyclically moving interior blade of conforming profile for shearing beard hairs, the combination comprising a plurality of ribs extending generally longitudinally along axes which are spaced generally parallel to one another, said ribs being of generally sinusoidal shape with adjacent ribs being out of phase with one another causing the spacing between them to continuously vary, and a plurality of rows of generally slit-shaped and closely spaced hair inlet holes respectively defined between the adjacent ribs, said holes extending generally from rib to rib so that the length of the respective holes as measured generally from rib to rib varies in accordance with the varying spacing between the ribs, said plurality of hair inlet holes comprising (a) a first group of holes in which the lengthwise axes of the generally slitshaped holes are oriented in a first direction slightly angled with respect to a perpendicular to the rib axes and (b) a second group adjacent thereto in which the lengthwise axes of the holes are oriented in a second direction angled differently from said first direction, said first and second groups of the hair inlet holes being located in each of the rows of the holes.
 2. The combination as claimed in claim 1 in which said first and second directions of the hole orientation in the respective first and second groups are angled by the same degree with respect to the rib axes so that hair holding angle for shearing will be constant over both groups of the holes.
 3. The combination as claimed in claim 1 in which said first and second directions of the hole orientation in the respective first and second groups are angled by different degrees with respect to the rib axes so that hair holding angle for shearing will be different in each of the groups. 